A linear actuator is provided with a coil and a drive magnet generating a magnetic flux which interlinks across the coil. As this type of linear actuator, the applicant has proposed a linear vibration actuator disclosed in parent literature 1.
This linear vibration actuator is provided with a cylindrical drive magnet magnetized in the axial direction and a coil disposed coaxially with the drive magnet so as to encircle the drive magnet. A magnetic flux generated by the drive magnet interlinks across the coil. By conducting electricity to the coil, either the coil or the drive magnet moves in the axial direction due to interaction between the magnetic flux of the drive magnet and the current flowing through the coil, thus making it possible to move. By switching the directions of the current flowing through the coil, that is, by supplying alternating current to the coil, the drive magnet vibrates in the axial direction.
At both axial ends of the coil, a pair of return magnets are arranged, which are for returning a mover to the starring point. The pair of return magnets repel the drive magnet of the mover so that the mover returns to the starting point due to the repelling force. With use of the repelling force of the magnet, it is possible to return the mover to the starting point without employing an elastic member such as a spring.